坡位对不同密度长白落叶松人工林生态系统碳储量的影响

Effects of Slope Position on Carbon Storage of Larix olgensis Plantation Forest Ecosystem with Different Stand Density

【目的】探明坡位对不同林分密度长白落叶松人工林生态系统碳储量及其分配特征的影响,为制定长白落叶松人工林增汇经营技术提供科学依据。【方法】以长白落叶松人工林为研究对象,利用生物量与含碳率估算植被层碳储量,土壤剖面法估算土壤层碳储量,并分析不同坡位、不同林分密度长白落叶松人工林生态系统的碳储量及其分配特征。【结果】上坡位和中坡位低密度长白落叶松人工林生态系统碳储量分别为236.69 t/hm^(2)和235.66 t/hm^(2),二者差异不显著;上坡位和中坡位高密度长白落叶松人工林生态系统碳储量分别为272.26 t/hm^(2)和330.72 t/hm^(2),中坡位生态系统碳储量显著高于上坡位。长白落叶松人工林生态系统碳储量依次为土壤层>植被层>凋落物层;高密度林分中坡位土壤有机碳储量占比显著低于高坡位,而植被层有机碳储量占比中坡位显著高于高坡位。【结论】立地条件对低密度林分的碳储量影响较小;对于高密度林分,立地条件好有利于提高植被层碳储量,中坡位择伐强度可适当加大,但不能超过上坡位的2倍。

【Objective】The effects of slope position on the carbon storage and allocation characteristics of Larix olgensis plantation forest ecosystem with different stand density are studied to provide the scientific basis for formulating the management technology for carbon sink increase of L.olgensis plantation forest.【Method】Taking L.olgensis plantation forest as the research object,the carbon storage in vegetation layer is estimated through biomass and carbon content,and the carbon storage in soil layer is estimated by soil profile method,then the carbon storage and its allocation characteristics of L.olgensis plantation forest ecosystem with different slope position and stand density are analyzed.【Result】The carbon storage of low-density L.olgensis plantation forest ecosystem in upper slopes and middle slopes are 236.69 t/hm^(2) and 235.66 t/hm^(2) with no obvious difference;The carbon storage of high-density L.olgensis plantation forest ecosystem in upper slopes and middle slopes are 272.26 t/hm^(2) and 330.72 t/hm^(2) respectively,and the ecosystem carbon storage of middle slopes is significantly higher than that of upper slopes.The carbon storage of L.olgensis plantation forest ecosystem follows soil layer>vegetation layer>litter layer;The proportion of soil organic carbon storage in middle slopes of high-density forest stand is significantly lower than that of upper slopes,while the proportion of organic carbon storage in middle slopes of vegetation layer is significantly higher than that of upper slopes.【Conclusion】Site conditions have little impact on the carbon storage of low-density forest stand;As for high-density forest stand,excellent site conditions are beneficial to improving the carbon storage in vegetation layer.The selective cutting intensity in middle slopes can be increased appropriately,but no more than two times of that in upper slopes.